In recent years, mobile terminals, such as quickly-developed smart phones, are used for work assistance at business, and homes in many cases. General mobile terminals are provided with a screen of a touch panel type serving as both image display and a user interface. Accordingly, a user can perform necessary input by touching this, and perform operations, such as displaying a desired image, and inputting information. However, in the case where user's hands have got wet or dirty, there may be a case where the user would like to operate a mobile terminal without touching a screen. Accordingly, at this time, how to perform input becomes a problem.
PTL 1 discloses a movable computing device equipped with an infrared LED and an infrared proximity sensor. According to the technique of PTL 1, when a hand is made to approach the movable computing device, infrared light rays emitted from the infrared LED are reflected on the hand, and the reflected light rays are detected by the infrared proximity sensor, whereby the movement of the hand can be detected. Furthermore, with the detected movement (a gesture) of the hand, an input operation desired by the user, such as a swipe, can be performed with a non-contact mode. Therefore, even if the user's hands have got dirty, there is no fear of polluting the movable computing device.